Seasonal heat storage improvements in Denmark
Over the last year, Danish companies managed to improve the cost and efficiency of seasonal pit heat storages. The size of these systems has grown considerably since the first big pit storage (10 000 m3 in Marstal), and prices are now set at a low 30 €/m3 for a pit heat storage with a 100 000 m3 or more capacity.
Vojens district heating
The consumer-owned district heating company Vojens Fjernvarme is one of the largest solar heating in the world, with 70 000 m2 of collectors, with one of the largest underground thermal storage pit (200 000 m3). The water volume is separated from the district heating water by a heat exchanger and the surface of the water is covered by the liner and an insulated cover and draining system. This storage is operated as an inter seasonal heat storage, which allows the solar plant to deliver more than half of the annual heat demand of the network.
Collectors area: 70 000 m2(Arcon Sunmark)
Storage: 200 000 m3 thermal pit
Other energy sources: 3xgas engines, 10 MW electric boiler, absorption heat pump, gas boilers
Installation year: 2016
Picture source: link 3